In an aircraft with a turbine engine, hot compressed air can be bled off from the turbine engine. This bleed air can be used for various functions, such as, for example, deicing of aircraft parts and air conditioning of a cabin, which typically involves heating and pressurizing the cabin. To that end, the aircraft is generally provided with a bleed air duct system. The bleed air duct system conveys the bleed air to aircraft parts that may require deicing, or to a fuselage of which the cabin forms part, or both. The bleed air duct system then traverses a pylon by means of which the turbine engine is suspended from a wing, and traverses the wing itself.
An overheating risk exists in an aircraft that uses air bled off from a turbine engine as described above. This bleed air is relatively hot. The bleed air duct system therefore radiates and convects heat when conveying bleed air. Moreover, in the bleed air duct system, there is a potential of bleed air leaking from joints, valves, and other elements that make up the bleed air duct system. Accordingly, aircraft parts that are relatively close to a bleed air duct run a risk of being heated to a critical temperature where structural strength may be compromised. This risk is particularly important for aircraft parts made of composite materials, which have a relatively low critical temperature.
There are several techniques for reducing the overheating risk identified above. For example, thermal insulation may be applied so as to protect aircraft parts from overheating. Another technique that may be applied is forced ventilation during flight. An overheating detection system may also be applied to prevent overheating. A cooling device may be provided near a point where bleed air is taken from the turbine engine. The cooling device may cool the bleed air before the bleed air is applied to the bleed air duct system so as to reduce the overheating risk.
US patent application published under number US 2010/028890 describes a wing-engine combination that includes an engine bleed air duct, which extends along a leading edge of a main wing. An inlet of the engine bleed air duct is coupled to an engine hot-air space. An outlet of the engine bleed air duct is coupled to a consumer of engine bleed air. An ambient air duct extends along the engine bleed air duct. Ambient air is let into in the ambient air duct. The engine bleed air duct and the ambient air duct form a heat exchanger for cooling engine bleed air flowing in the engine bleed air duct.